From bbe97dff8b3054d96e758f486f9ce3fa09e64de3 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Thu, 5 Dec 2019 19:11:09 +0100 Subject: Make the Store API more type-safe Most functions now take a StorePath argument rather than a Path (which is just an alias for std::string). The StorePath constructor ensures that the path is syntactically correct (i.e. it looks like /-). Similarly, functions like buildPaths() now take a StorePathWithOutputs, rather than abusing Path by adding a '!' suffix. Note that the StorePath type is implemented in Rust. This involves some hackery to allow Rust values to be used directly in C++, via a helper type whose destructor calls the Rust type's drop() function. The main issue is the dynamic nature of C++ move semantics: after we have moved a Rust value, we should not call the drop function on the original value. So when we move a value, we set the original value to bitwise zero, and the destructor only calls drop() if the value is not bitwise zero. This should be sufficient for most types. Also lots of minor cleanups to the C++ API to make it more modern (e.g. using std::optional and std::string_view in some places). --- src/libexpr/eval.hh | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'src/libexpr/eval.hh') diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh index 85aa1ccfe..cabc92d15 100644 --- a/src/libexpr/eval.hh +++ b/src/libexpr/eval.hh @@ -17,6 +17,7 @@ namespace nix { class Store; class EvalState; +struct StorePath; enum RepairFlag : bool; @@ -42,14 +43,14 @@ struct Env }; -Value & mkString(Value & v, const string & s, const PathSet & context = PathSet()); +Value & mkString(Value & v, std::string_view s, const PathSet & context = PathSet()); void copyContext(const Value & v, PathSet & context); /* Cache for calls to addToStore(); maps source paths to the store paths. */ -typedef std::map SrcToStore; +typedef std::map SrcToStore; std::ostream & operator << (std::ostream & str, const Value & v); -- cgit v1.2.3